1. Field of the Invention
The present invention relates to an apparatus and a method for removing a sheet applied to a plate-shaped member such as a semiconductor wafer.
2. Description of the Prior Art
When a semiconductor is manufactured, a grinding process is carried out on the underside surface of a semiconductor wafer (hereafter referred to simply as xe2x80x9cwaferxe2x80x9d) in order to create a thin, miniaturized semiconductor chip, but before such grinding process is carried out, a protecting sheet made from an adhesive film or the like is bonded to the upper surface (i.e., the surface formed with the circuit) of the wafer. Then, after grinding is completed, the protecting sheet is removed.
In Japanese Laid-Open Publication No. 11-16862, the present inventors have proposed a novel method of removing a protecting sheet applied to a plate-shaped member by using an adhesive tape with a prescribed length wherein the adhesive tape is bonded to an end of the sheet and the adhesive tape is pulled to remove the sheet.
As a result of repeated experimentation, it has been observed that, in the foregoing method, there is a risk that the sheet is occasionally stretched or torn off along the outer periphery thereof when the adhesive tape is pulled in a direction parallel to the plane of the wafer in order to remove the sheet.
It is an object of the present invention to remove without failure the sheet applied to the plate-shaped member without resulting stretching or tear of the sheet.
To achieve the foregoing object, the present invention provides an apparatus for removing a sheet applied to a plate-shaped member by using an adhesive tape with a prescribed length by bonding the adhesive tape to an edge portion of the sheet followed by pulling the adhesive tape, characterized by comprising means for pulling the sheet obliquely upwardly.
The means for pulling the sheet obliquely upwardly may comprise guide means for guiding the direction of pull of the sheet. The term xe2x80x9cobliquely upwardlyxe2x80x9d is intended to mean a direction excluding the direction parallel to the wafer surface and includes, for example, a direction wherein the angle formed with the wafer surface is 5xc2x0-175xc2x0. The direction of pull may be the same as the direction in which the sheet is applied or, alternatively, the sheet may be pulled in the reverse direction.
In another aspect, the present invention provides an apparatus for removing a sheet applied to a plate-shaped member by using an adhesive tape with a prescribed length by bonding the adhesive tape to an end of the sheet followed by pulling the adhesive tape, characterized by comprising a guide roller disposed in the vicinity of the sheet to ensure that the sheet is pulled as it is turned over the guide roller. In this case, the guide roller may be disposed in such a position as to prevent upward movement of the plate-shaped member.
According to a still another aspect of the invention, there is provided a method for removing a sheet applied to a plate-shaped member by using an adhesive tape with a prescribed length, the method comprising the steps of bonding said adhesive tape to an end of the sheet and pulling the adhesive tape obliquely upwardly to thereby remove the sheet away from the plate-shaped member.
According to a further aspect of the invention, there is provided a method for removing a sheet applied to a plate-shaped member by using an adhesive tape with a prescribed length, the method comprising the steps of bonding the adhesive tape to an end of the sheet and pulling the adhesive tape with the sheet turned over a guide roller.
It should be noted that even though the present invention is particularly suited to removing a protecting sheet applied to a wafer, the present invention is not limited to such case, and instead the present invention provides a general apparatus and method for using an adhesive tape to remove a sheet applied to a plate-shaped member. The plate-shaped member may further include glass plate, plastic plate, painted steel plate, ceramic plate, printed circuit board, liquid crystal plate, optical element plate, etc. The present invention can be applied to remove a protecting sheet applied to these members.